Valve for electro-pneumatic railroad-brakes



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J. F. CARPENTER.

VALVE EOE ELECTRO PNEUMATIG EAILEOAD BRAKES.

No. 378,658. Patented Feb. 28, 1888.

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J. F. CARPENTER.

VALVE EUR ELECTRO PNEUMATIG RAILROAD BRAKES. No. 378,658. Patented Feb. 28, 1888.

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"NrTn STATES PATENT trice.

J. FAIRFIELD CARPENTER, OF BERLIN, GERMANY.

VALVE FOR ELECTR-PNEUMATIC RAILROAD-BRAKES.

SPECIFICATION forming part of Letters Patent No. 378,658, dated February 28, 1888.

Application tiled September 12, 1887. Serial No. 249.518. (No model.)

To @ZZ whom, it may concern:

Be it known that I, J. FAIRFIELD CARPEN- TER, a citizen of the United States, residing at Berlin, Prussia, Germany, have invented a certain new and useful Improvement in Valves for Electro-Pneumatic Railroad-Brakes, of which the iollowing is a full, clear, and eXact description.

rIhe object of this invention is to provide a valve mechanism for pneumatic railwaybrakes which may be operated electro-pneumatically to apply and release the brakes, or may be operated pneumatically alone for the same purpose. This valve mechanism is designed to be operated either by means of an electric current which acts upon supplemental valves to cause a reduction of air-pressure in the valve-box only, (the air-pressure in the main pipe being unaii'ected,) thereby causing the brakes to actin the usual way, or the valve mechanism may be operated solely by variations of the air-pressure in the main pipe, which is used to convey the air to the ordinary auxiliary reservoirs under each car in a train of cars.

The invention is herein set forth as constructed for use in those systems of air-brakes whichcomprise air-compressing apparatus and a main reservoir on the locomotive, air-pipes leading therefrom to the auxiliary reservoirs under each car, a brakecylinder under each car, and a valve interposed between the brakecylinder, reservoir, and main pipe; and inasmuch as said systems are well known and in common use, no further description thereof is deemed necessary herein.

Stated in very broad and general terms, the invention consists in a valve mechanism constructed and arranged substantially as hereinafter particularly set forth and claimed, and adapted to be operated either electro-pneumatically or pneumatically to operate the brakes.

In the accompanying drawings, in the several gures of which like parts are similarly designated, Figure 1 is a vertical section of the valve mechanism, one piston-head and one magnet-bor. being shown in elevation. Fig. 2 is a transverse section. Fig. 3 is a horizontal section, both of the piston-heads being shown in elevation, excepting that part of the piston B is broken away to show a leak-hole, Fig. 3ft, details of the pistonol and valves c ddetached. Fig. 4 is a section similar to Fig. l. with the valve in position 'for applying the brakes. Figs. 5 and 6 are longitudinal and transverse sections of a modification.

A is the valve box or case.

B and B are pistons rigidly arranged upon a connecting-stem, BZ.

(lis a slide-valve rigidly affixed upon the stem B2 between the pistons.

D D are electro-magnets arranged in cases secured to the valve-box A. Each elec-tro` magnet is provided with an armature, E,Which is secured to a stem, E', the upper end of which is provided with a Valve, F, the said valve having its seat in the upper end of the tubular portion E2. The armature E is normally pressed from the electro-magnet by :a spring, E3, and this spring at the same time serves to normally seat the valve F. Conductors G G' are connected with the magnets D D', respectively.

The valve mechanism is connected to the main pipe by the passage a, and a port, b, leads to a chamber, II, on one end of the valve-box, and this chamber is separated from the main valve-chamber by the wall b', in which is arranged an opening provided with a checkvalve, c. Within the chamber H is arranged a piston, d, which is provided with a checkvalve, d', covering a central port or opening in the said piston. d isa compartment inthe chamber II. Springs d3 and d4 are arranged Within the chamber H, and bear, respectively, upon the check-valves c and d. The valveboX is divided into chambers e, f, and f2, and the chambers f and f2 communicate through a leak-hole, f', in the pistons B. A passage or port, g', serves to connect the valve-case and the auxiliary reservoir, and the said passage or port opens into the valve-case in the chamber f-that is to say, between the pistons B and B. A passage or port, 7L, serves as the means of communication between the brakecylinder and the valve, and an exhaust-port, z', is arranged in the valve case or box and communicates with the brake-cylinder through the port h and the ports 7c in the slide-valve C. The chamber e communicates with the external atmosphere through the ports Zmand the tubular post E2, and a similar communication of the chamber fz is had through the port Z and other openings in the electro magnet chamber D. Imay here remark that the valve F and the similar valve in the electro-magnet D are herein referred to as supplemental valves. A weighted check-valve, rv, is interposed between the inlet a and the chamber f. A leak-hole, n, is arranged in the wall b'. A spring, o, is interposed between the piston B and the wall b.

The construction and arrangement of parts being substantially as herein indicated, I will now proceed to describe the operation.

Air from the main pipe,entering at @,passes thence through the passage b into the chamber H and on the right-hand side of the pistonvalve d. This has the effect of moving the said piston toward the left, and the checkvalves c and d being connected, and the said check-valve d being seated on the left-hand side of the said piston d, the said valve c will be opened, thereby admitting the air from the said valve c into the chamber e. This will have the effect of driving the pistons B B, together with the slide-valve C, into the position shownin Figs. 1 and 3. The valvex is weighted to about fifteen pounds pressure, and hence will be opened to admit air into the chamber f only when that pressure is overcome, which it will be by the incoming air fresh from the main reservoir at the locomotive. The air passes from the chamberf through the port g to the auxiliary reservoir. In this position the brakes are off- 77 Now, if the electro-magnet D be energized, its armature E will be lifted, and thus the valve Fwill be opened. The result is that the air in the chamber c is free to escape through the ports Z and m and past the valve F into theatmosphere. This will leave an excess of pressure in the chambers f and f2 and the communicating auxiliary reservoir, whereby the pistons B B will be moved to carry the slidevalve C past the port h, thereby closing the exhaust-port and allowing the air to pass from the auxiliary reservoir through the port h to the cylinder and apply the brakes. i The chamber e cannot be refilled from the main pipe during this operation, because the valve cwill be closed by its pressure, the small leak-hole not being able to overcome lthe waste at the open valve F. When the brake has been applied with sufiicient force, the electric current is cut off from the magnet D, wherebyits armature E drops and closes the valve F. Airpressure from the main pipe will then enter the chamber e through the small leak-hole n, and, equilibrium being thus restored on all sides of the pistons B B, the spiral spring o will force the said pistons, together with the slide-valve C, into an intermediate return position, where further iiow of air from the auxiliary reservoir to the cylinder through the port h is cut olif. In this position the brakes can be held on as l'ong as desired.

To release the brakes, an electric current is sent through the other conductor, G', energizing the magnet D', lifting its armature, and opening its supplemental valve, and thus exhausting into the atmosphere through the port Z, the chamber f2 back of the piston B', and causing the pistons B B, and with them the slide-valve C, to complete the stroke to the right and obtain the position shown in Figs. 1, 2, and 3 ofthe drawings, in which position, it will be observed, the brake-cylinder is open to the external atmosphere through the ports h 7c i, thus releasing the brakes. Now, when the electric current through the conductor G is cut off, equilibrium is again restored through the small leak-hole f and the valve mechanism remains in the released position shown.

To work the valves by means of variations of air-pressure in the main air-pipe alone, instead of in conjunction with electricity, I proceed as follows: Air is first charged through the valves into the auxiliary reservoir the same as before. To apply the brake, the airpressure in the main pipe is suddenly reduced. The check-valve x thus becomes operative to prevent the return flow of air from the chamber j' and auxiliary reservoir to the main pipe, and at the same time, the pressure being thus suddenly taken oli' the piston d and its valve c, the pressure in the chamber e will open the said valve c, andthe air in said chamber thus escape through said valve and the port back into the maiirpipe. This will destroy the equilibrium of the pistons B B', and hence said pistons and the slidevalve C will be moved over to the left, as before, uncovering the port h and permittingthe flow of air from the auxiliary reservoir to the brake-cylinder and applying the brakes. When the air passes fr`om the reservoir to the cylinder in putting on the brakes, (by ain) the pressure in the auxiliary reservoir will naturally be reducingitself until it reaches a point at or below that of the main pipe which had previously been reduced by letting out air to put on the brakes. This is the point of equilibrium7 where pressures are equal in the pipe and in the reservoir, and the spring o will act to move the valve C into position to cut off further supply of air to the brake-cylinder. To release the brakes, the air-pressure in the main pipe is suddenly raised, land the air, passing through port b and into the chamber H,will again push back the piston d, thereby raising the valve c and recharging the chamber e with a higher pressure, which will effect the completion of the return-stroke of pistons B B and slide-valve C into the released position shown, thereby exhausting the brake-cylinder through the ports h 7c fi. To accomplish satisfactorily these double functions-that is to say, working the valve electropneumatically or simply pneumatically-by means of one and the same valve mechanism, it is necessary to automatically open and close the connection between the main pipe and the chamber e, for in working the brake electric- ICO IIO

through the comparatively small valve F, and

a large communication with the main pipe cannot, therefore, be allowed; but in working the brake pneumatically a large free communication between the main pipe and chamber eis absolutely necessary in order to insure quick application and release. The arrangement of the valves c and d and piston d, however, permits this to be accomplished, for it has been shown that the valve c remains closed .while applying the brakes by means of electricity, but that it is opened when applying and releasing the brakes pneumatically. It should be here remarked that any air-pressure which may leak past the piston d into the compartment d2 of the chamberI-I is removed when working the brakes by air, for as soon as the pressure at b is reduced the piston d will moveto the right, thus openingits valve d and permitting the excess of pressure from behind to pass through the opening in the piston d with which the valve d co-operates, and thence escape out through port b.

In Figs. 5 and 6 I have shown a modification ofthe invention which differs more'in arrangement tlian in aught else, excepting that I employ a common three-way stop-cock, P, leading to the check-valve c, as a substitute for the valvular apparatus shown in the chamber H ofthe other iigurcs.

As a mechanical equivalent for the pistons shown in Figs. l, 2, 3, and 4, and a full substitute in purpose, effect, and operation therefor, I have shown in Figs. 5 and 6 flexible diaphragms united by a common stem, as are the pistons before referred to; but instead of having the leak-hole n in the wall b, I make said leak-hole of right-angular outline in one end of the stem, and,instead of having a leakhole, JU, in the diaphragm, I arrange it of similar outline in the opposite end of said stem.

As will hereinafter more particularly appear, the stopcock l) is not automatic, but is to be operated by hand in changing from the pneumatic to the electric working ofthebrake. In electrically working the valve shown in Figs 5 and 6 the stop-cock l? is turned into the position shown, so that air from the main pipe passes through the port o to the checkvalves x and c. At the same time there is out off by this plug the port bx, which leads to the chamber @,so that air from the main pipe can only reach the chamber 6 through the small leak-hole n, Fig. 5.

To work the brake pneumatically,the plug P is given a half-turn, so as to open both the ports b and bx, and then the chamber e will have a large communication with the main pipe through the port bX without passing the check-valves c or m.

In the claims hereinafter made, although I have used the word piston to apply to the devices B and B, I wish to be understood as including in said term the diaphragms shown in the modification; and so, also, in reference to the device interposed between the thusqualied piston and the main pipe, I have used the generic terni valve, and in said term I desire to be understood as including the stopcock P, inasmuchas such stop-cock is simply one form of valve.

l/Vhat I claim is- 1. An electro pneumatic railway brake Valve mechanism, comprising a valve-box, a double piston arranged therein, a slidevalve operated by the said piston and controlling communication between the auxiliary reservoir, brake-cylinder, and atmosphere, a valve interposed between the main pipe and one end of this double piston, and an electric valve controlling communication of the chamber between the last-named valve and piston and the atmosphere, substantially as set forth.

2. A valve for pneumatic railway-brake systems, comprising a valve-box, a double piston arranged in said valve-box, a slide-valve connected to said double piston and controlling communication between the auxiliary reservoir, brake-cylinder, and atmosphere, and a compound piston-valve interposed between one end of said double piston and the main airpipe, and adapted to admit air into the valvebox between itself and said end ofthe double piston to operate the said double piston and slide-valve to release the brakes, and also operable by a reduction of pressure of the main air-pipe to exhaust the air from the aforesaid chamber, and thereby permit the movement of the double piston in the opposite di rection to apply the brakes, substantially as set forth.

In testimony whereof I have hereunto set my hand this 6th day of September, A. D. 1887.

J. FAIRFIELD CARPENTER. Vitnesses:

J. W. HowsoN, R. IMMisoH. 

